I am not sure of the assigned technical reason, but offer this possibility based on my study.
First, until your post, I had never noticed the dimple in the extended 8round mag. I had noticed that it is more difficult to load the last couple of rounds in the extended mag than it is in the standard 6round mag. My opinion is that the dimple is there to assist in keeping the nose of the next to last round contained and pointing down toward the base of the mag to help prevent it from pushing up on the last round and dislodging it to he point that it wants to eject. The mag spring is very robust and wants to push the last round out. Rarely are added manufacturing steps incorporated by large manufacturers that add cost for no reason.
If others have a better opinion or know for certain the reason for the dimple, I would be interested in hearing from them.
First, until your post, I had never noticed the dimple in the extended 8round mag. I had noticed that it is more difficult to load the last couple of rounds in the extended mag than it is in the standard 6round mag. My opinion is that the dimple is there to assist in keeping the nose of the next to last round contained and pointing down toward the base of the mag to help prevent it from pushing up on the last round and dislodging it to he point that it wants to eject. The mag spring is very robust and wants to push the last round out. Rarely are added manufacturing steps incorporated by large manufacturers that add cost for no reason.
If others have a better opinion or know for certain the reason for the dimple, I would be interested in hearing from them.
